1. Field
Embodiments described herein generally relate to reference voltage generators that provide temperature-independent reference voltages.
2. Background
Many integrated circuits (ICs), e.g., application-specific integrated circuits (ASICs), include circuit blocks that require a constant reference voltage to maintain proper operation. A problem arises when even small changes in temperature can cause variance in the actual reference voltage which degrades the performance of the circuit blocks.
A bandgap reference voltage generator is a device that internally compensates for the typical fluctuation of reference voltage with temperature. For example, these generators typically produce the reference voltage which is independent of temperature fluctuations, at least to the first order. However, operation of these generators is dependent on ideal component behavior. In practice, the components are not ideal. Thus, the actual output voltage of the generator can still vary and may deviate from a specific expected value.
Calibration of these generators can be used as a way to obtain ideal component behavior. Calibration, however, can be a time-consuming and expensive process. For example, calibration requires the use of sophisticated testing equipment. This equipment can often be used for a large number of different circuits, thus time spent calibrating reference generators takes away from time that could be used to calibrate other circuits. Moreover, complex calibration techniques needed for sensitive circuits may require especially complex circuitry in the reference voltage generator. Furthermore, a device may have a large number of voltage generators, thereby multiplying the total time and expense associated with calibration.